5

LTC1504A

TEST CIRCUITS

SHDN

SS

COMP

GND

SW

FB/SENSE

+

100

µF

NC

0.01

µF

+

220

µF

47

µH

1504A • TC01

LTC1504A

1

µF

0.1

µF

220pF

7.5k

Figure 1

+

–

LTC1504A

COMP

FB/SENSE

A

B

1504A • TC02

Figure 2

Figure 3. Block Diagram

+

–

+–

FB

–+

+

12

µA

12

µA

PWM

12.6k

20.4k

Q1

Q2

SW

FB

(ADJ ONLY)

SENSE

(–3.3V ONLY)

SAW

SS

COMP

SHDN

1504A • BD

TO INTERNAL BLOCKS

OVERVIEW

The LTC1504A is a complete synchronous switching

regulator controller (see Block Diagram). It includes two

on-chip 1.3

Ω power MOSFETs, eliminating the need for

external power devices and minimizing external parts

count. The internal switches are set up as a synchronous

buck converter with a P-channel device (Q1) from the

input supply to the switching node and an N-channel

device (Q2) as the synchronous rectifier device from the

switching node to ground. An external inductor, input and